What causes sleep paralysis?

It is normal for your muscles to be paralysed at certain times when you are asleep. Sleep paralysis occurs when the mechanism that causes your muscles to relax during sleep temporarily persists after you have woken up.

Sleep paralysis can sometimes be a symptom of narcolepsy. This is a relatively rare sleep disorder that causes a person to fall asleep suddenly and unexpectedly, disrupting their normal sleep pattern.

Symptoms

The main symptom of sleep paralysis is a temporary inability to move or talk.

The paralysis usually happens as you are waking up, but it can also sometimes happen when you are falling asleep.

Not being able to move or talk can be very frightening, particularly as you will be completely conscious throughout the experience.

During an episode of sleep paralysis, you may also experience a very real sensation that there is someone else in the room with you.

These type of hallucinations are a fairly common feature of sleep paralysis, although they do not occur in every case.

The length of time that you are unable to move for can vary from a few seconds to several minutes. After this, you will be able to move and speak as normal.

Immediately after an episode of sleep paralysis you may feel unsettled and anxious. However, the condition does not pose a risk to your overall health.

Many people only experience sleep paralysis once or twice in their life. If it happens several times a month or more regularly, it is known as isolated sleep paralysis.

Causes

Sleep paralysis is caused when hormones produced by the body to help you sleep do not wear off as you wake up.

This means that you remain temporarily paralysed but conscious.

REM sleep

To understand better what causes sleep paralysis, it is useful to know what usually happens when you are asleep.

Sleep occurs in cycles and each cycle is split into two phases – rapid eye movement (REM) sleep and non-REM sleep.

The brain is very active in REM sleep and most dreams occur at this stage of sleep. Also, during REM sleep the body is paralysed, apart from the movement of the eyes and diaphragm (the main muscle used in breathing). The paralysis is thought to occur to prevent you acting out the actions in your dreams.

Sleep paralysis occurs when the normal muscular paralysis of REM sleep temporarily continues after you have woken up.

Increased risk

Certain factors make you more likely to get sleep paralysis:

age – it is more common in teenagers and young adults

sleep deprivation – sleep paralysis is more common in people who do not get enough sleep

irregular sleeping patterns – people with irregular schedules or who work shifts are more prone to sleep paralysis

narcolepsy – some people with narcolepsy (a sleep disorder where you suddenly fall asleep at inappropriate times) also experience sleep paralysis

family history – you may be more likely to have sleep paralysis if another member of your family also has it; however, this is an area where further research is needed

Treatment

Ensuring you get enough sleep and improving your sleeping environment will help if you have sleep paralysis. In severe cases, medication may be recommended.

Sleeping habits

Sleep paralysis is more common in people who are sleep deprived, so getting enough sleep may help reduce the number of episodes of sleep paralysis. Most adults need 6-8 hours of sleep each night.

Keeping to a regular sleeping schedule, where you go to bed at roughly the same time each night and get up at the same time each morning, can also help.

Tips for improving your sleeping habits include:

creating a restful sleeping environment that is quiet, dark and not too hot or cold

ensuring your bed is comfortable

exercising regularly (but not too close to bedtime)

cutting down on caffeine

not eating or drinking alcohol before bedtime

giving up smoking (if you smoke) because nicotine is a stimulant

Medication

If your sleep paralysis is particularly troublesome, you may be prescribed a short course of antidepressant medication, such as a tricyclic antidepressant (TA), typically [clomipramine].

Antidepressants affect mood and are usually used to treat depression, but are also sometimes prescribed to treat severe sleep paralysis.

The medication is thought to work by altering the amount and depth of REM sleep. This should prevent the temporary paralysis when you wake up or fall asleep, and it should also help reduce any hallucinations you may have.

You may be advised to take the medication for a month or two to see whether it improves your symptoms.

Gareth's story

Gareth Fletcher, 32, regularly had sleep paralysis when he was a teenager. Although it has virtually stopped, he still experiences it very occasionally.

"I first experienced sleep paralysis when I was 16.

"I remember it vividly. I went to bed one night as usual, but at some point I woke up and was unable to move a muscle. I was conscious and aware that I was in my bed, but my entire body was paralysed.

"It may have only lasted a matter of seconds, but the experience was terrifying. There was a ringing noise in my ears that seemed to get louder, and no matter how hard I struggled, I couldn't move. I had a feeling of immense panic, and an urgent need to move my arms and legs.

"Then suddenly I could move again. While this was a great relief, I was still scared as I had no idea what had just happened.

"The same thing happened again a few nights later, and then it began to happen regularly. Often, it would happen a couple of times in the same night.

"I became nervous about going to sleep – worried that every time I went to bed I’d wake up and be unable to move. Even though the paralysis was only temporary, it was very frightening.

"Often, I would wake up suddenly after having a vivid dream. Sometimes this was an unpleasant dream, which made the experience even scarier.

"I didn’t tell anybody about it at first. This was partly because I began to doubt that it was really happening. I thought perhaps I was dreaming it, and although it seemed very real at the time, perhaps it was just a nightmare in which I couldn’t move.

"Also, it happened as I was falling asleep early in the night. By the time I'd woken up in the morning, it didn't seem to matter so much and I tried to forget it had happened.

"Then one day at school, I overheard a friend talking about a documentary he'd seen about this very phenomenon. It was the first time I'd heard the term 'sleep paralysis', and it perfectly described what happened to me – although my friend mentioned that the people on TV had also felt a presence in the room and a pressure on their chest when they woke up, which I hadn't had.

"Knowing that it had a name was a relief. I told my parents about it, and my dad said it happened to him once when he was younger. My mum has since said it once happened to her too.

"My mum then told our doctor, who said it was nothing to worry about and that little was really known about it. The doctor did say she thought it may be linked to stress.

"The sleep paralysis kept happening, but I no longer felt so panicked by it. It was still very unpleasant and I had a desperate need to move every time I woke up, but I just told myself that it was nothing sinister and I’d be able to move in a few seconds.

"And then it stopped happening, almost overnight, when I went to university. It's odd, but it seemed to happen only when I was in my bed at home. After I left, it virtually disappeared.

"It does happen now, but only extremely rarely. It can still be frightening, mainly because of the disorientation you feel when you suddenly wake up and can't move. But knowing what's happening and that it's nothing to worry about makes it bearable, and I'm usually able to relax and get back to sleep quickly."

Commmon Sleep paralysis questions

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What causes sleep paralysis?

Sleep paralysis may occur when rapid eye movement (REM) sleep is disrupted. It is during REM sleep, a stage of sleeping, that our brain is most active and the body enters a state of paralysis. If the transition between sleep stages doesn’t run smoothly and you wake up, you become aware of your body’s paralysis, and you can experience an inability to speak or move.

How do you get sleep paralysis?

Sleep paralysis occurs when you wake up before the rapid eye movement (REM) sleep cycle has finished. You will be conscious, but the muscles in your body won’t be able to move.

Anyone can experience sleep paralysis, but some are at higher risk. People who are more likely to encounter sleep paralysis are those who have experienced some kind of trauma, have disrupted sleep cycles or are sleep deprived, or suffer from other types of sleep disorders, like narcolepsy.

Is sleep paralysis a sleep disorder?

Sleep paralysis is a disruptive sleep disorder, otherwise known as a parasomnia. Other types of parasomnias include sleepwalking and nightmares.

What are the stages of sleep paralysis?

There are no specific stages of sleep paralysis. During sleep paralysis you wake up the muscles are not working, so you cannot move and feel paralysed. An episode of sleep paralysis is usually brief, ranging from a few seconds to a few minutes.

How does sleep paralysis feel?

People can experience a feeling of dread or fear. You may also experience difficulty breathing, an inability to move or speak, tightness in the chest, or even hallucinations.

Are there ways to prevent sleep paralysis?

There are changes you can make to help prevent sleep paralysis. Try sticking to a regular sleep routine, make sure you get enough sleep, and find ways to improve sleep quality, such as sleeping on a comfortable mattress and pillow.

Is there a cure for sleep paralysis?

There is no cure for sleep paralysis, but if you suffer from sleep paralysis there are things you can do to reduce the risk of it occurring again. Make sure you get enough sleep and try to stick to a routine sleep schedule. Also, make your sleeping environment as restful as possible. If sleep paralysis is a real problem, you can be prescribed antidepressant medication.

Is sleep paralysis common?

Sleep paralysis is common. It’s estimated that four in 10 people will experience sleep paralysis at some point in their lives. However, sleep paralysis is more common in teenagers and young adults.

Why do you hallucinate during sleep paralysis?

Some people experience hallucinations as they fall asleep or just before waking up. If the hallucinations occur while falling asleep, they are called hypnagogic, and if the hallucinations occur while waking up, they are called hypnopompic.

Are there any natural remedies for sleep paralysis?

There are lifestyle changes you can make to reduce the risk of sleep paralysis. Try to stick to a regular sleep schedule and avoid drinking caffeine or alcohol close to bedtime. Try not to look at electronic devices just before you go to bed, as the blue light from your smartphone can lead to sleep disruption. Aim to make your sleeping environment as comfortable as possible.